Integrated plastic circuits based on OFETs are used for microelectronic mass applications and disposable products such as identification and product tags. A tag is, for example, an electronic bar code of the kind provided on merchandise or on luggage. OFETs have a wide range of uses as RFID tags: radio frequency identification tags, which need not be arranged only on the surface. In the case of OFETs for these applications, the excellent operating behavior of silicon technology can be dispensed with, but by the same token low production costs and mechanical flexibility should be ensured. The components, such as, for example, electronic bar codes, are typically disposable products and of interest economically only if they are produced in economical processes.
To date, owing to the production costs, only the conductor layer of the OFET has been structured. Structuring can only be realized using a two-stage process (“lithography method”, cf. in this respect Applied Physics Letters 73(1), 1998, p. 108.110 and Mol. Cryst. Liq. Cryst. 189, 1990, p. 221-225) with firstly uniform exposure and subsequent structuring, which moreover is material-specific. “Material specificity” means that the process described, with the photochemical components mentioned, only function on the conductive organic material polyaniline. A different conductive organic material, e.g. polypyrrole, cannot readily be structured in this way.
The lack of structuring of the other layers, such as at least the structuring of semiconducting and of the insulating layer comprising functional polymers (which may be present in polymeric or oligomeric form), leads to a substantial reduction in performance of the OFETs obtained, but it is dispensed with for cost reasons. The structured layer can be structured by other known methods (such as, for example, printing) only in such a way that the length l , which denotes the distance between source and drain electrodes and is therefore a measure of the power density of the OFET, is at least 30 to 50 μm. However, lengths l of less than 10 μm are desirable, and hence at present no structuring method apart from the complicated lithography method appears reasonable.